The present invention relates to a serial printer in which print operation is performed by using the ink supplied from an ink cartridge attached to the printer. The term "ink cartridge" is used in this specification to cover both an ink cartridge, in a narrow sense, used in ink jet printers and an ink ribbon cartridge used in impact printers.
Serial printers such as an ink-jet printer and an impact printer use an ink cartridge detachably attached to the printer. For example, when the ink in the cartridge has been used up or the ink ribbon has been dried up due to a large volume of print or long period of use, the ink cartridge is replaced with a new, unused cartridge.
Generally, a serial printer is designed to use the ink specially designed for the printer. An accidental use of an ink cartridge having different ink characteristics of the designed ink will result in poor print quality and/or damage to the print head. For example, for ink jet printers, differences in ink viscosity cause troubles such as poor print quality and clogging of the nozzle of the print head. For impact printers, differences in composition of the ink of the ink ribbon will cause the pins of the print head to rapidly wear out and greatly decreases the life of the print head.
In order to determine whether the ink cartridge attached to the printer is a proper type, each type of ink cartridge is conventionally provided with a particular projection and the projection is detected by the printer when attached to the printer. Alternatively, an ink cartridge is provided with a piece of permanent magnet and the magnet is detected by a Hall-sensor in the printer. However, the problem is that it is difficult to determine whether or not an ink cartridge is suitable for use with the printer if the ink cartridge is filled with ink not suitable for use with that serial printer but is of the same shape as or very close in physical shape to the cartridge filled with suitable ink. If an ink cartridge is designed to be too simple to check whether or not the cartridge is suitable for use with that printer, copy products of that type of ink cartridge may readily be produced, leading the users to accidental use of an ink cartridge not suitable for the printer.